In an automatic transmission for a vehicle, the speed change ratio is varied automatically according to vehicle speed or throttle opening, etc. Apart from the automatic operation mode, a speed change control device which permits manual operation by a driver is disclosed in Tokkai Hei 5-322022 published by the Japanese Patent Office in 1993.
This device comprises an operating lever for the driver to input a shift-up command or shift-down command into the speed change control device. In manual mode speed change, the automatic transmission performs shift-up or shift-down operations according to the operating direction and operating frequency of the operating lever. That is to say when, for example, the operating lever is moved twice in the shift-down direction from fourth speed, a shift-down to second speed from fourth speed is performed.
However, when operations of the operating lever are successively performed in the same direction, the speed changes abruptly from fourth speed to first speed in a short time, and as a result the driver experiences an excessive engine braking sensation.